CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > Phoenics

variable heat source

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   April 7, 2003, 12:21
Default variable heat source
  #1
John
Guest
 
Posts: n/a
Hi:

I met a problem for the variable heat source. For example, the fire in the building can be taken as heat source in the simulation. But at the first stage, the heat power is: Q=a*t**2, Q is heat power, a is a constant, t is time. Only the linear heat source with time is given in software. How can I defined t-square heat source in the simulation.

Thank a lot! John
  Reply With Quote

Old   April 7, 2003, 22:50
Default Re: variable heat source
  #2
Leon Mills
Guest
 
Posts: n/a
John,

Other may have better anwser but I tend to do the following.

Q = A for t = 0 to 60sec Q = B for t = 60 to 120 sec ....

with time increments to suit you liking.

If you select the time increments appropriately and save them intheir own Q1 file it can be simple to cut and paste you fire into a new model.

Hope this helps

Leon
  Reply With Quote

Old   April 8, 2003, 03:18
Default Re: variable heat source
  #3
Rami
Guest
 
Posts: n/a
Hi John,

A general form for your source can be introduced via GROUND coding, where you have access to most of the variables. This approach, however, assumes you are familiar with GROUND structure and the variable names and storage, and also can program in FORTRAN.

There are two alternatives (which I never tried myself) that are supposed to facilitate this task: PLANT and the newly introduced INFORM.

All the above is described in CHAM's site. You can also try to contact their support with your specific form of the source.

I hope this helps,

Rami
  Reply With Quote

Old   April 8, 2003, 12:12
Default Re: variable heat source
  #4
John Ludwig, CHAM
Guest
 
Posts: n/a
Say the source you want is 100*t^2 W/m^3, limited to 10000 W/m^3.

To create a time-squared heat source (for the variable TEM1) using In-Form, you need to create a PATCH where you want the heat source to be. In VR-Editor, you can make a User-Defined object, and in its Attributes dialog make a new patch called, say, HEAT. Set the type to VOLUME.

In the Q1, either by hand, or using the In-Form Editor, add the lines:

inform13begin (source of tem1 at heat is min(100*tim^2,10000))

inform13end

If hand-editing, save Q1 and reload working files. Run Earth. This should do it.

For more details on In-Form, look in http://www.cham.co.uk/phoenics/d_pol...nc/in-form.htm
  Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Additional Variable Source alvio CFX 0 March 4, 2009 15:34
Units of additonal Variable and its source Gauranga Das CFX 2 December 6, 2007 04:59
Input heat source (heat/unit volume) in 2D Polly FLUENT 2 March 18, 2005 02:04
variable source on the interface Yi Zhang CFX 0 May 17, 2004 13:49
variable heat source simulation LI Y FLUENT 1 April 8, 2003 00:46


All times are GMT -4. The time now is 22:37.